Gyro-magnetic compass



Oct. 8, 194 L. F. CARTER 2,217,515

' GYM-MAGNETIC COMPASS Filed Dec. 2:5, 1938 IN ENTOR Lag/E HRTER Patented Oct. 8, 1940 (am-MAGNETIC COMPASS Leslie F. Carter, Leonia, N. J., assignor to Sperry Gyroscope Company, Inc., Brooklyn, N. Y., a corporation of New York Application December 23, 1938, Serial No. 247,311

5 Claims.

This invention relates to improvements in direction indicating instruments of the gyroscopic type for-airplane'use, and especially to the gyro-magnetic compass. Such.instruments 5 have been built and used in a variety of forms, but in all of them the necessity of setting the gyrosoopic element initially onto the course in-- dicated by the magnetic element requires complicated and sometimes inconvenient additions 10 to the apparatus and occupies too much time of the pilot and his attention while resetting the instrument.

- The purpose of this invention is to provide an improved means of causing the gyroscopic ele-- it is very difilcult to overcome excessive loss of air in such devices, as the clearance between moving parts has to be large enough to prevent mechanical-contact, thereby allowing so much I) air to escape, that the 'device is only operative in a limited way. This invention improves the resetting device in a novel way and thereby insures reliable functioning without excessive loss of air.

8 This invention is applicable generally to any direction maintaining gyroscopic instrument, and by way of illustration, I show it as applied to a gyro-magnetic compass, in which the gyroscopic element is controlled in known manner 49 by a magnetic element.

In the drawing,

Fig. 1 shows an elevation section through the housing of a gyro-magnetic compass according to my invention, with certain'parts sectioned or a partly sectioned.

Y Fig. 2 shows an'enlarged section of a part 0! Fig. 1 along line 1-1.

Fig. 3 is a top view of the resetting knob and.

the mechanism associated therewith.

50' Fig. 4 is an enlarged elevation view of part of Fig. 3.

Fig. 5 is'a front view of the resetting knob. The gyro-magnetic compass shown in the drawing is of a type shown in my prior copending application Serial No. 165,661, for Gyromagnetic compasses, filed September 25, 1937. It therefore becomes unnecessary to go into a detailed description of the gyro-magnetic compass itself or its principle of operation. In Fig. 1, the casing i is shown in the conventional way as closed by a cover plate 2 having a transparent window 3. Air is exhausted from this casing through pipe 4 in the usual way, the air entering into the casing I through a screen 5 in the bottom thereof. The'vertical frame 6 of the gyro-magnetic compass is carried on air fiow films which are established between the cup members 'I and- 8 attached to the easing I, and spherical members 9 and ill, shaped to closely fit said cups and attached to the verti- 1i cal frame 6. Another set .of similar cups II and II, are carried on the vertical frame 6, and serve,

. by means of an air film, as bearings for the rotor bearing casing l3 which contains the gyro rotor, the spin axis of which is normally horizontal and perpendicular to' the plane oi the drawing.

The magnetic element I4 is suspended on the rotor bearing casing l3 and, in known manner, controls the gyroscopic member and its preces- 25 sion by means of air jets and vanes l5, as fully described in my aforementioned copending application. In order to cause the gyroscopicelement, which in this case is composedfflof the gyro rotor, the rotor bearing casing l3 and the 80 vertical frame 6., to 'precess around the vertical axis at will, or forvobtaining adjustment'of the card or dial l6 of the instrument, it is necessary to apply a torque to the rotor bearing casing ll around a horizontal axis normal to the axis or Y the gyroscope. The horizontal axis around which this torque is applied is ther'eforelocated in the plane of the drawing of Fig. 1. I prefer to apply this torque by means of air jets which can be controlled at will by the opera ator, and the arrangement of which is shown in Fig. 2. A toothed sector 11 is fastened to the top of the rotor bearing casing I! in such away that it is closely adjacent to'two apertures ll and I9 located in the 'upper spherical member 9 of the vertical frame 6. These apertures are inclined with respect to the vertical so that if air issues irom them, the jets would strike the teeth of the sector I! in a'substantiallynormal direction; During ordinary operation both the go apertures 18 and I9 are inoperative, a valve stem I 20 shutting,ofl the air supply tothe circular re-' -cesses 2i and 22 which are connected by passages 23 and. 24- to the openings II and It, rev spectively. .The valve stem 2| is hollow at its l6 lower end and has a number of holes 25 drilled through its cylindrical wall. In the position shown, these holes are closed and the stem is held in its position by means of small balls 26 and 21 pressed into a circular recess by means of a spring 28. Another recess 30 is located above the recess and a recess 31! is located below the recess, the distances of these recesses being so arranged that if the valve stem is pulled up until it locks in recess 30, the holes 25 will register with the recess 22. If the valve stem is depressed until the detent snaps into the recess 3|, the holes 25 will register with the circular recess 2|. A number of slots 33 are milled into the cylindrical wall of the valve stem so that air always can enter into the interior of the valve stem from the air passage 34, which completely surrounds the valve stem.

The top of the valve stem. projects into a chamber 60, closed against the atmosphere by a plate 6|. As shown in Fig. 4, the stem 20 has a groove 35 into which two pins 31 and 31* (Fig. 3) project. 'These pins are carried on a fork 38 which is pivoted at 39 in bearing member 40 and 4| mounted on the casing I. The forked member 38 extends beyond thepivot 39 and is slotted at its other end to allow a pin 42 to register therewith. This pin is mounted on a shaft 43 connected to the setting knob 44 located outside of the housing. Three detents 45 are provided in this shaft so that a ball and spring lock mechanism 46 will arrest the shaft 43 in itsneutral position and after turning it 90 degrees either way. By turning the knob 84 from its neutral position in a clockwise direction towards the letter H engraved on the outer surface of the housing, as shown in Fig. 5, the fork 38 is lifted, thereby lifting the valve stem 20 until it is locked in the upper detent 30 by means of its ball and spring locking mechanism. In this position both the valve stem and the shaft 43 are held in such a way that there is no mechanical contact between them. In this way the detents serve the purpose of separating the fork and the valve stem so that friction cannot develop around the vertical axis of the vertical frame 6, which might otherwise cause precession of the gyroscopic element.

By raising the valve stem to its upper position, air is admitted into the space 22 and will issue from the aperture l8, forming a jet, the energy of which is expanded upon the toothed sector l1, thereby exerting a torque in counter-clockwise direction upon the rotor bearing housing around the horizontal axis of this member. This torque will cause rapid precession of the gyroscoplc member around the vertical axis, thereby taking along the dial i6. This precession will continue as long as the valve stem remains in its raised position and will stop immediately as the knob 44 is returned to its neutral position, indicated by 0 as shown in Fig. 5. If the knob ll is turned in counter-clockwise direction until the pointer 50 registers with .the figure L" in Fig. 5, the valve stem is depressed and air is admitted to the passage 2| so that a jet is formed by aperture l9, causing a clockwise torque upon the which point he turns the knob 44 back to its neutral position to stop further precession.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description -or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim and desire to secure by Letters Patent is:

1. In an azimuth indicating free or directional gyroscope having an outer casing, a vertical ring rotatably mounted therein, a compass card fixed to said ring and a rotor bearing frame pivoted in said ring on a horizontal axis; a novel means for resetting said card and ring at will comprising a pair of oppositely directed air jets turnable with said ring, intercepting means on said frame against one or the other of which said jets strike to exert a torque about the horizontal axis of said frame to cause precession in azimuth, a two way valve concentric with the vertical axis for supplying air to said jets, said valve having a stem projecting through said easing into an airtight chamber, means in said chamber operable from without for lowering, centering and raising said valve stem tooperate said valve, and separate means for arresting separately said operating means and said valve stem in said three different positions in such a way as to prevent mechanical contact between the former and the latter.

2. In an azimuth indicating free or directional gyroscope having an outer casing, a vertical ring rotatably mounted therein, and a rotor bearing frame pivoted in said ring on a horizontal axis, means for resetting said ring at will comprising a pair of oppositely directed air jets turnable with said ring, intercepting means on said frame against one or .the other of which said jets strike to exert a torque about the horizontal axis of said frame to cause precession in azimuth, a three position sliding valve normally closed in its center position and slidably mounted in said ring .concentric to its vertical axis and adapted to provide air to one Jet in its lower position and to the other jet in its upper position, a stem for torques about the horizontal axis of said bearing casing in either direction, a three position valve means extending through the vertical axis of the upper button for leading air to one or the other of said airjets or shutting off both, and a knob without said outer casing for operating said valve to any of said three positions.

4. In an azimuth indicating free or directional gyroscope having an outer casing, a vertical ring rotatably mounted therein, a compass card fixed to said ring and a rotor bearing frame pivoted in said ring on a horizontal axis; a novel means for resetting, said card and ring at will comprising a pair of oppositely directed air J'ets turnable with said ring, intercepting means on said frame aamoie against one or the other of which said .iets strike to exert a torque about the horizontal axis 0! said frame to cause procession in azimuth, a two way means for resetting said ring comprising a pair' 1 of oppositely directed air jets turnable with said -ring, intercepting means on said irame against one or the other of which said jets strike to exert a torque about the horizontal axis of said frame to cause precession in azimuth, 'a three position sliding valve normally closed inits center posi-i tion and slidably mounted in said'ring and adapted to provide air to one jet in one extreme position and .to the other jet in its other extreme position, and means for moving the valve to precess the gyroscope in azimuth in either direction.

1 LESLIE F. CARTER, 

